Keywords
aorta - acute aortic dissection - aortic pseudoaneurysm - imaging - surveillance
A 72-year-old female with a medical history of hypertension, interstitial lung disease,
and obstructive sleep apnea underwent elective mitral valve repair for posterior leaflet
prolapse using a 30-mm MitroFix™ device. The aortic root and ascending aorta had normal
dimensions. Following removal of the aortic root vent on discontinuation of cardiopulmonary
bypass, a bluish discoloration of the ascending aorta was evident, with visible ascending
aortic dilatation. Transesophageal echocardiography confirmed an acute DeBakey type
II aortic dissection. Ascending aortic replacement was therefore performed using a
26-mm Gelweave™ (Terumo UK Ltd.) interposition graft with 4/0 polypropylene suture
under hypothermic circulatory arrest at 18 °C alongside antegrade cerebral perfusion.
The patient made an uncomplicated recovery and was discharged home.
Three months postoperatively, the patient reported progressive dyspnea, prompting
a transesophageal echocardiogram. This demonstrated preserved biventricular function,
mild central aortic regurgitation, trace mitral regurgitation, and an intact ascending
aortic graft. Chest X-ray ([Fig. 1]) revealed widened mediastinal appearances and small bilateral pleural effusions.
Her respiratory symptoms at this stage were attributed to preexisting pulmonary disease.
Fig. 1 Chest X-ray demonstrating mediastinal widening 3 months postoperatively.
With further symptomatic deterioration at 6 months postoperatively, transthoracic
echocardiography demonstrated an ascending aortic pseudoaneurysm measuring 8.1 cm.
Urgent computed tomography angiogram of the aorta ([Figs. 2]
[3]
[4]) revealed a giant aortic pseudoaneurysm arising just superiorly to the right coronary
ostium via a 2.4-cm orifice and measuring 8.2 cm in maximal cranio–caudal dimension.
Fig. 2 Coronal computed tomography scan demonstrating a giant aortic pseudoaneurysm (asterisk)
arising from just above the right coronary ostium.
Fig. 3 Axial computed tomography scan demonstrating the giant aortic pseudoaneurysm (asterisk).
Fig. 4 Three-dimensional computed tomography scan demonstrating the aortic pseudoaneurysm.
The patient underwent an emergency redo sternotomy for resection of the pseudoaneurysm
and replacement of the aortic root using a Freestyle® (Medtronic, Inc.) prosthesis.
She unfortunately succumbed postoperatively to severe bleeding complications in the
intensive care unit.
Aortic pseudoaneurysms may develop in 10 to 24% following surgery for acute Type A
aortic dissection[1] and predispose to dissection, rupture, and embolization. In retrospect, however,
our patient's postoperative presentation with dyspnea may well have been a manifestation
of the enlarging pseudoaneurysm's compressive effects on adjacent lung parenchyma
or cardiac structures. We propose that localized infection or an intraoperatively
undetected technical issue involving the proximal anastomosis adjacent to the right
coronary ostium may potentially have induced pseudoaneurysm formation in this case.
Special attention must be paid to the critical technical aspects of dissection repair,
particularly the meticulous performance of anastomoses in fragile tissues, and imperfections
that can risk delayed suture line dehiscence. While successful percutaneous repair
of aortic pseudoaneurysms has been reported,[2] an open surgical approach was planned for our patient owing to the large size of
the pseudoaneurysm, its broad neck, and proximity to the right coronary ostium.
The present case highlights the importance of close postoperative surveillance with
periodic cross-sectional imaging at intervals specified by departmental protocols,
or sooner on clinical or radiological suspicion of an adverse event, to permit the
timely identification and optimal management of aortic complications.
